Most animals are required to interact with a complex environment. That is, a successful individual must do more than passively observe regularities in the natural world. Foraging, hunting, mating, escape from predators, and a host of other survival-related behaviors require the skillful execution of complicated sequences of actions. In these situations, it is the sequence of actions, and not the component actions themselves that are of particular interest. The proposed research is part of a long-term effort to investigate how animals learn and execute complex sequences of behaviors. Seven experiments in this proposal will develop and elaborate on a pigeon version of a widely used Serial Response Time task, originally developed in the context of human neuropsychology research. The basic procedure requires pigeons to peck a series of illuminated keys that occur according to a predictable pattern, and sequence learning is indicated by faster average response times as they gain experience executing the sequence. Each of the proposed experiments isolates a different component of sequence learning and attempts to specify the range of conditions under which effective sequence learning occurs. These experiments will identify the kinds of complex sequences that pigeons can readily learn and execute, and develop a new empirical procedure that connects sequence learning with the extensive literature on spatial attention and visual categorization. By developing a nonhuman animal version of a procedure that is widely used in neuropsychology, the project will open up the possibility of research into the biological basis of sequence learning. Such an animal model would prove particularly valuable in the investigation of several neurological disorders such as temporal lobe amnesia and Parkinson's disease. [unreadable] [unreadable] [unreadable]